[FFmpeg-devel] [PATCH 2/2] webmdashenc: Support for live stream manifests
Vignesh Venkatasubramanian
vigneshv at google.com
Wed Apr 1 04:38:39 CEST 2015
On Tue, Mar 31, 2015 at 6:58 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Tue, Mar 31, 2015 at 04:51:58PM -0700, Vignesh Venkatasubramanian wrote:
>> This patch adds support for creating DASH manifests for WebM Live
>> Streams. It also updates the documentation and adds a fate test to
>> verify the behavior of the new muxer flag.
>>
>> Signed-off-by: Vignesh Venkatasubramanian <vigneshv at google.com>
>
> [...]
>
>> @@ -79,19 +89,42 @@ static double get_duration(AVFormatContext *s)
>>
>> static void write_header(AVFormatContext *s)
>> {
>> + WebMDashMuxContext *w = s->priv_data;
>> double min_buffer_time = 1.0;
>> + time_t local_time;
>> + struct tm* gmt;
>> + char* gmt_iso = av_malloc(21);
>> avio_printf(s->pb, "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
>> avio_printf(s->pb, "<MPD\n");
>> avio_printf(s->pb, " xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n");
>> avio_printf(s->pb, " xmlns=\"urn:mpeg:DASH:schema:MPD:2011\"\n");
>> avio_printf(s->pb, " xsi:schemaLocation=\"urn:mpeg:DASH:schema:MPD:2011\"\n");
>> - avio_printf(s->pb, " type=\"static\"\n");
>> - avio_printf(s->pb, " mediaPresentationDuration=\"PT%gS\"\n",
>> - get_duration(s));
>> - avio_printf(s->pb, " minBufferTime=\"PT%gS\"\n",
>> - min_buffer_time);
>> - avio_printf(s->pb, " profiles=\"urn:webm:dash:profile:webm-on-demand:2012\"");
>> - avio_printf(s->pb, ">\n");
>> + avio_printf(s->pb, " type=\"%s\"\n", w->is_live ? "dynamic" : "static");
>> + if (!w->is_live) {
>> + avio_printf(s->pb, " mediaPresentationDuration=\"PT%gS\"\n",
>> + get_duration(s));
>> + }
>> + avio_printf(s->pb, " minBufferTime=\"PT%gS\"\n", min_buffer_time);
>> + avio_printf(s->pb, " profiles=\"%s\"%s",
>> + w->is_live ? "urn:mpeg:dash:profile:isoff-live:2011" : "urn:webm:dash:profile:webm-on-demand:2012",
>> + w->is_live ? "\n" : ">\n");
>> + time(&local_time);
>
>> + gmt = gmtime(&local_time);
>
> this should be using gmtime_r() please see libavutil/time_internal.h:
>
Done.
>> + strftime(gmt_iso, 21, "%FT%TZ", gmt);
>> + if (w->debug_mode) {
>> + av_strlcpy(gmt_iso, "", 1);
>> + }
>> + if (w->is_live) {
>> + avio_printf(s->pb, " availabilityStartTime=\"%s\"\n", gmt_iso);
>> + avio_printf(s->pb, " timeShiftBufferDepth=\"PT%gS\"", w->time_shift_buffer_depth);
>> + avio_printf(s->pb, ">\n");
>> + avio_printf(s->pb, "<UTCTiming\n");
>> + avio_printf(s->pb, " schemeIdUri=\"%s\"\n",
>> + w->utc_timing_url ? "urn:mpeg:dash:utc:http-iso:2014" : "urn:mpeg:dash:utc:direct:2012");
>> + avio_printf(s->pb, " value=\"%s\"/>\n",
>> + w->utc_timing_url ? w->utc_timing_url : gmt_iso);
>> + }
>> + av_free(gmt_iso);
>> }
>>
>> static void write_footer(AVFormatContext *s)
>> @@ -137,33 +170,47 @@ static int bitstream_switching(AVFormatContext *s, AdaptationSet *as) {
>> * Writes a Representation within an Adaptation Set. Returns 0 on success and
>> * < 0 on failure.
>> */
>> -static int write_representation(AVFormatContext *s, AVStream *stream, int id,
>> +static int write_representation(AVFormatContext *s, AVStream *stream, char *id,
>> int output_width, int output_height,
>> int output_sample_rate) {
>> + WebMDashMuxContext *w = s->priv_data;
>> AVDictionaryEntry *irange = av_dict_get(stream->metadata, INITIALIZATION_RANGE, NULL, 0);
>> AVDictionaryEntry *cues_start = av_dict_get(stream->metadata, CUES_START, NULL, 0);
>> AVDictionaryEntry *cues_end = av_dict_get(stream->metadata, CUES_END, NULL, 0);
>> AVDictionaryEntry *filename = av_dict_get(stream->metadata, FILENAME, NULL, 0);
>> AVDictionaryEntry *bandwidth = av_dict_get(stream->metadata, BANDWIDTH, NULL, 0);
>> - if (!irange || cues_start == NULL || cues_end == NULL || filename == NULL ||
>> - !bandwidth) {
>> + if ((w->is_live && (!filename)) ||
>> + (!w->is_live && (!irange || !cues_start || !cues_end || !filename || !bandwidth))) {
>> return -1;
>> }
>> - avio_printf(s->pb, "<Representation id=\"%d\"", id);
>> - avio_printf(s->pb, " bandwidth=\"%s\"", bandwidth->value);
>> + avio_printf(s->pb, "<Representation id=\"%s\"", id);
>> + // FIXME: For live, This should be obtained from the input file or as an AVOption.
>> + avio_printf(s->pb, " bandwidth=\"%s\"",
>> + w->is_live ? (stream->codec->codec_type == AVMEDIA_TYPE_AUDIO ? "128000" : "1000000") : bandwidth->value);
>> if (stream->codec->codec_type == AVMEDIA_TYPE_VIDEO && output_width)
>> avio_printf(s->pb, " width=\"%d\"", stream->codec->width);
>> if (stream->codec->codec_type == AVMEDIA_TYPE_VIDEO && output_height)
>> avio_printf(s->pb, " height=\"%d\"", stream->codec->height);
>> if (stream->codec->codec_type = AVMEDIA_TYPE_AUDIO && output_sample_rate)
>> avio_printf(s->pb, " audioSamplingRate=\"%d\"", stream->codec->sample_rate);
>> - avio_printf(s->pb, ">\n");
>> - avio_printf(s->pb, "<BaseURL>%s</BaseURL>\n", filename->value);
>> - avio_printf(s->pb, "<SegmentBase\n");
>> - avio_printf(s->pb, " indexRange=\"%s-%s\">\n", cues_start->value, cues_end->value);
>> - avio_printf(s->pb, "<Initialization\n");
>> - avio_printf(s->pb, " range=\"0-%s\" />\n", irange->value);
>> - avio_printf(s->pb, "</SegmentBase>\n");
>> + if (w->is_live) {
>> + // For live streams, Codec and Mime Type always go in the Representation tag.
>> + avio_printf(s->pb, " codecs=\"%s\"", get_codec_name(stream->codec->codec_id));
>> + avio_printf(s->pb, " mimeType=\"%s/webm\"",
>> + stream->codec->codec_type == AVMEDIA_TYPE_VIDEO ? "video" : "audio");
>> + // For live streams, subsegments always start with key frames. So this
>> + // is always 1.
>> + avio_printf(s->pb, " startsWithSAP=\"1\"");
>> + avio_printf(s->pb, ">");
>> + } else {
>> + avio_printf(s->pb, ">\n");
>> + avio_printf(s->pb, "<BaseURL>%s</BaseURL>\n", filename->value);
>> + avio_printf(s->pb, "<SegmentBase\n");
>> + avio_printf(s->pb, " indexRange=\"%s-%s\">\n", cues_start->value, cues_end->value);
>> + avio_printf(s->pb, "<Initialization\n");
>> + avio_printf(s->pb, " range=\"0-%s\" />\n", irange->value);
>> + avio_printf(s->pb, "</SegmentBase>\n");
>> + }
>> avio_printf(s->pb, "</Representation>\n");
>> return 0;
>> }
>> @@ -208,6 +255,53 @@ static int check_matching_sample_rate(AVFormatContext *s, AdaptationSet *as) {
>> }
>>
>> /*
>> + * Parses a live header filename and computes the representation id,
>> + * initialization pattern and the media pattern. Pass NULL if you don't want to
>> + * compute any of those 3. Returns 0 on success and non-zero on failure.
>> + *
>> + * Name of the header file should conform to the following pattern:
>> + * <file_description>_<representation_id>.hdr where <file_description> can be
>> + * anything. The chunks should be named according to the following pattern:
>> + * <file_description>_<representation_id>_<chunk_number>.chk
>> + */
>> +static int parse_filename(char *filename, char **representation_id,
>> + char **initialization_pattern, char **media_pattern) {
>> + char *filename_str;
>> + char *underscore_pos = NULL;
>> + char *period_pos = NULL;
>> + char *temp_pos = NULL;
>
>> + filename_str = av_mallocz(strlen(filename) + 1);
>> + if (!filename_str) return AVERROR(ENOMEM);
>> + strncpy(filename_str, filename, strlen(filename));
>
> av_strdup
>
Done.
> [...]
> --
> Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> If you think the mosad wants you dead since a long time then you are either
> wrong or dead since a long time.
>
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>
--
Vignesh
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